1. Field of the Invention
This invention relates to means for deterring operation of an internal combustion engine, such as used in a motor vehicle, and has particular reference to means for preventing operation of the ignition system and for rendering it difficult to detect such means.
2. Description of the Prior Art
Generally, the ignition system of a motor vehicle engine is controlled by a key lock operated switch to prevent theft or unauthorized operation of the vehicle. A proper key is thus generally required to release the lock and close the ignition switch in order to complete the ignition circuit. However, auto thieves and others can usually "hot wire" or short across the open contacts of the ignition switch and thus complete the circuit through the ignition system so as to start the engine.
Attempts to foil auto thieves from "hot wiring" an ignition system of a motor vehicle heretofore have usually comprised providing a hidden switch somewhere in the ignition circuit, in addition to the conventional ignition switch, so that even though the ignition switch is closed or shorted, the ignition circuit will not be completed. However, knowledgeable persons can readily detent the fact that the ignition circuit is incomplete and thus readily find and complete the circuit, as by using an additional conductor across the open portion of the circuit.
Other attempts have been made to render an ignition system inoperative by connecting a settable switch across the positive and negative terminals of the ignition coil. However, this procedure results in shorting out the coil and consequent overheating when the settable switch and the ignition switch are closed concurrently. Such overheating can readily cause damage to related components and even cause the motor vehicle itself to catch fire.